High polarization, endurance and retention in sub-5 nm Hf0.5Zr0.5O2 films
J. Lyu, T. Song, I. Fina, and F. Sánchez
Nanoscale 12, 11280 (2020)
Ferroelectric HfO2 is a promising material for new memory devices, but significant improvement of its important properties is necessary for practical application. However, previous literature shows that a dilemma exists between polarization, endurance and retention. Since all these properties should be simultaneously high, overcoming this issue is of the highest relevance. Here, we demonstrate that high crystalline quality sub-5 nm Hf0.5Zr0.5O2 capacitors, integrated epitaxially with Si(001), present combined high polarization (2Pr of 27 μC cm−2 in the pristine state), endurance (2Pr > 6 μC cm−2 after 1011 cycles) and retention (2Pr > 12 μC cm−2 extrapolated at 10 years) using the same poling conditions (2.5 V). This achievement is demonstrated in films thinner than 5 nm, thus opening bright possibilities in ferroelectric tunnel junctions and other devices.
Unraveling Ferroelectric Polarization and Ionic Contributions to Electroresistance in Epitaxial Hf0.5Zr0.5O2 Tunnel Junctions
M. Cervo Sulzbach, S. Estandía, X. Long, J. Lyu, N. Dix, J. Gàzquez, M. F. Chisholm, F. Sánchez, I. Fina,* and J. Fontcuberta*
Adv. Electron. Mater. 2019, 1900852
Tunnel devices based on ferroelectric Hf0.5Zr0.5O2 (HZO) barriers hold great promises for emerging data storage and computing technologies. The resistance state of the device can be changed through use of a suitable writing voltage. However, the microscopic mechanisms leading to the resistance change are an intricate interplay between ferroelectric polarization controlled barrier properties and defect‐related transport mechanisms. The fundamental role of the microstructure of HZO films determining the balance between those contributions is demonstrated. The HZO film presents coherent or incoherent grain boundaries, associated to the coexistance of monoclinic and orthorhombic phases, which are dictated by the mismatch with the substrates for epitaxial growth. These grain boundaries are the toggle that allows to obtain either large (up to ≈450%) and fully reversible genuine polarization controlled electroresistance when only the orthorhombic phase is present or an irreversible and extremely large (≈103–105%) electroresistance when both phases coexist.
Plenary talk on 14th December 2017 at the workshop “Multifunctional oxides: Sinergy between fundamental science and novel technologies” by Gervasi Herranz
MilenaSulzbach, granted by INphINIT-La Caixa, joints our team to work on “Engineering brain-like neurons and synapses with ferroelectrics”. Welcome Milena
Next 21st June, Prof. Dr. Martin Bowen will give the lecture”Oxide and organic tracks toward nanospintronics within solid-state devices”
Wednesday, 21 June: INVITED SEMINAR “Oxide and organic tracks toward nanospintronics within solid-state devices” by Prof. Dr. Martin Bowen, Institut de Physique et Chimie des Matériaux de Strasbourg, France.
PLUGIN JB LIBRARY DEBE ESTAR DESACTIVADO PARA QUE FUNCIONEN LOS SLIDESHOW
Degree in Physics (University of Barcelona). Final degree project “Magneto-optical spectroscopy of ferromagnetic garnet thin film” with Gervasi Herranz and Blai Casals.